抄録
Tooth germs of first and second molars of both jaws obtained from new born mice of inbred strains were stained with alizarin red S dye and examined under a stereoscopic microscope. For numerical analysis a stage number assigned was converted to the calcification rate using calcium content of samples from a given stage. Although each molar presented a rather distinctive sequence and pattern of calcification, there were considerable variations within strains in several stages. A statistical method to reduce the component of variance due to factors other than age was proposed by the author and used. Curvilinear regression was applied to elucidate the growth curve of calcification of molars. In the examination of bilateral symmetry in calcification, low symmetry was observed at the beginning of spurt of calcification and A/J strain showed relatively lower symmetry than other strains. Sex difference was not observed in the growth of calcification.
